What is often overlooked and misunderstood is that the bulbs were not only valued for their beauty, but more importantly for their use as commercial breeding stock.

Since it was not possible to reproduce the best bulbs through seed propagation, the already rare buds themselves were the only source of producing future varieties exhibiting the same beautiful patterns. This goes a great way to explaining the high prices paid, and debunking the myth of irrationality.

"The tulip market involved only bulbs affected by a mosaic virus which had the effect of creating beautiful, feathered patterns in the flowers. Only diseased bulbs were valued by traders, because a particular pattern could not be reproduced through seed propagation. Only through budding of the mother bulb would a pattern breed true." - Garber, Famous First Bubbles https://www.aeaweb.org/articles?id=10.1257/jep.4.2.35